Why is Fe an abundant element on earth, and why are the elements with higher atomic numbers increasingly rare?

i) The elements having a lower value of reduction electrode potential are abundant on earth crust. Fe is abundant on earth crust along with other elements having low value of reduction electrode potential (above hydrogen in electro chemical series). The elements with higher atomic numbers have higher reduction electrode potential and hence do not occur on earth crust (below hydrogen in electro-chemical series).

ii) The high abundance of iron on earth is due to its very high nuclear binding energy which makes it highly stable. On other hand, the element with higher atomic numbers have relatively low nuclear binding energy and hence are relatively unstable and have rare abundance.